In conventional color digital imaging, a pixel color value is detected due to a color mosaic deposited on a surface of an image sensor, which is known in the art as the Bayer mosaic. The use of the Bayer mosaic for color separation results in different colors being detected in different pixels of the image sensor and, therefore, different points of the captured image, which results in color aliasing. Color aliasing is a phenomenon in which the colors of the fine details of the image are distorted, or false colors are detected along the edges and fine details of the image.
To decrease the phenomenon of color aliasing, an optical low-pass filter (OLPF) is usually added to a digital camera. This filter partially blurs the image, decreasing the color aliasing phenomenon, but simultaneously decreasing the image resolution. Furthermore, the OLPF is usually based on polarizing properties of optical birefringence materials and fails to properly work under the conditions of polarized illumination, thereby limiting use of polarization techniques and degrading the image quality under the polarized illumination.
Furthermore, in conventional digital cameras, the image formed on the image sensor should be simultaneously sharp for all the colors of the spectrum. Therefore, great efforts are taken to correct the chromatic aberrations of the lenses, which is an intrinsic property of glass lenses. However, correction of chromatic aberrations results in significantly more expensive, bigger and bulkier lenses, and degradation of other optical properties, such as a significant decrease of maximum aperture, an increase of the minimal focal length, etc.